RA-230.76985, DEC--0.51657. MJD-51673, Plate- 313, Fiber-275 PIl HeIsil Ma Dill Na NIILI call Call [10- erg cm 's 1-] 4000 5000 Z- 0.0284, +/- 0.0001 (9.98), Galaxy, 6000 7000 8000 9000 Wavelength [R] Making the Hubble Diagram Now that you have magnitudes and redshifts for ten galaxies, you are ready to make a color Hubble diagram. Place on the x-axis (horizontal) the magnitude values (start with "u") and in the y-axis (vertical) the red-shift values from your table. Include a trend line equation in your color Hubble diagram (to model linearity). The points in your diagram should roughly follow a straight line, if not review your data for outliers! Repeat this process for other magnitude values: g, r, i and z PRINT your PLOTS ! Do your data really show a linear relationship between magnitude and redshift? When scientists try to find relationships in data, they often speak of a "model"; in this case, a linear model relates magnitude to redshift. Scientists often speak of the "fit" between the data and the model. The fit can be described with a percentage that shows how close the points lie to the place where they should lie if the model were true. Because every experiment has some error and every observation has some statistical uncertainty, the fit is never 100% accurate. Generally, scientists consider a fit above 90% to show that the model accurately predicts the data From you plots and linear fit equations let find the average and relative error to slope values filter slope g r Z average Extracted from Sloan Digital Sky Server Astronomy Projects, http://cas.sdss.org/dr7/en/